1. Field of the Invention
The present invention relates to an attaching structure for a seatbelt apparatus of a vehicle equipped with a seat, which is supported by a vehicle body through a weight sensor.
2. Description of Relevant Art
In the conventional three-point support type seatbelt apparatus (hereinafter indicated as seatbelt apparatus), one end of a seatbelt is stored in a retractor, which adjusts the length of a seatbelt by allowing the pull-out/take-up of the seatbelt. The other end of the seatbelt is fixed to a vehicle floor that is in the vicinity of the side-part of a vehicle seat. In this seatbelt apparatus, the seatbelt is guided by a slip guide positioned on a level with a shoulder of a vehicle seat.
The seatbelt has a tang placed between the slip guide and the seatbelt-anchor. When using this seatbelt apparatus, the tang is engaged with a buckle fixed to the vehicle floor that is in the vicinity of the other side-part of the vehicle seat. Thereby, the occupant sitting on the seat (vehicle seat) is held by the seatbelt that is supported at three points (the slip guide, the seatbelt-anchor, and the buckle).
Generally, the seatbelt is used for holding the occupant on the seat. But, the seatbelt apparatus is also used in order to fix a child seat to the vehicle seat.
In the conventional seatbelt apparatus, the pull-out and take-up of the seatbelt is managed in compliance with the prescribed operation mode. In other words, the adjustment of the length of the seatbelt is managed in compliance with the prescribed operation mode. Here, a term “pull-out” means that the pulling out of the seatbelt stored in the retractor, in order to lengthen the length of the seatbelt. A term “take-up” means that the storing of the seatbelt into the retractor in order to shorten the length of the seatbelt. As an example of the operation mode, an emergency lock mode and an auto lock mode can be cited.
Here, the adjustment of the length of the seatbelt is managed based on the emergency lock mode, when collision with another vehicle occurs and the seatbelt is pulled at a speed of more than a threshold speed. That is, this emergency lock mode is performed in order to protect the occupant against injury by holding the occupant by the seatbelt.
On the other hand, the adjustment of the length of the seatbelt is managed based on the auto lock mode, when fixing the child seat to the vehicle seat. In this mode, the pull-out of the seatbelt is forbidden and the take-up of the seatbelt is allowed. Thereby, the child seat is firmly fixed at the vehicle seat without causing the stagger of the child seat.
As an example of these types of the seatbelt, the seatbelt apparatus disclosed in Japanese unexamined patent publication JP H11-245753 can be cited.
Recently, a vehicle seat equipped with a weight sensor that measures a weight of an occupant has been widely spread. These types of the vehicle seat are also widely adopted in the intelligent control of the equipments of the vehicle.
When the child seat is fixed to the vehicle seat equipped with the weight sensor utilizing the auto lock mode, the child seat is pushed against the vehicle seat by the tension of the seatbelt (hereinafter a belt tension) that is caused in the region between the seatbelt-anchor and the buckle. In this occasion, since the seatbelt-anchor is fixed at the lower part of the vehicle body, the child seat is pushed downwardly by the belt tension.
In this occasion, since the force (load), which pushes the child seat against the vehicle seat, acts on the weight sensor, the weight sensor also detects the load caused by the belt tension in addition to the weight of the occupant and the child seat.
Thus, this may give a lower reliability of the detection result of the weight sensor. Thereby, the miss operation of the airbag may be caused when the deployment of the airbag is controlled based on the detection result of the weight sensor.
Therefore, the attaching structure of a seatbelt apparatus, which can prevent the occurrence of the detection error that occurs when the weight of the occupant is measured by the weight sensor, has been required.